Research on Variation of Precipitation and Runoff in the Liushahe Watershed in 1959～2000

Based on survey data during 1959～2000,the interannual variations and their trends of the Liushahe watershed mean precipitation and runoff and the relationship between the two were analyzed.The results show that there is no marked trend for precipitation from 1959 to 2000,especially in dry season.While runoff diminished from 1960s and increased from middle 1990s.And runoff coefficient has grown markedly since 1959.The amplitude of interannual variations of precipitation and runoff is on the decrease,especially runoff.Precipitation impacts runoff greatly,but the effect has lessened.So Liushahe watershed runoff has been impacted by other factors,which has been greater with time.